[PATCH v3 docs 43/76] storage: lvm: note the rescan after extending a shared volume group

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

LVM hints can hide a PV added by another node to an existing shared
volume group. Automatic discovery only retries groups missing entirely,
not groups with missing PVs. Document how to rescan after extending a
shared group, including that the rescan resets LVM autoactivation
records.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 pve-storage-lvm.adoc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/pve-storage-lvm.adoc b/pve-storage-lvm.adoc
index ba78663..f00688d 100644
--- a/pve-storage-lvm.adoc
+++ b/pve-storage-lvm.adoc
@@ -121,6 +121,15 @@ A benefit of LVM is that it can be used with shared storage.
 For example, an iSCSI LUN. The backend implements proper cluster-wide locking if
 the storage is marked as shared in the configuration.
 
+NOTE: If you extend a shared volume group onto another device on one node, the
+other nodes may only see the added physical volume after LVM has scanned their
+devices again, for example with `pvscan --cache`. This command also resets the
+autoactivation records of LVM, which can let LVM activate logical volumes on its
+own later. {pve} disables autoactivation for the logical volumes it creates.
+Before you run the command, make sure that autoactivation is also disabled for
+all other logical volumes of the volume group, for example with
+`lvchange --setautoactivation n <vg>/<lv>`.
+
 TIP: You can use the LVM-thin backend for non-shared local storage. It supports
 snapshots and linked clones.
 
-- 
2.47.3